1. Field of the Invention
The present invention relates generally to the field of navigation and/or position tracking, including a personal navigation system and, in particular, to a navigational system initialization and deployment system, process, and arrangement.
2. Description of the Related Art
The present invention relates generally to devices, systems, and methods of determining the location of mobile personnel and, particularly, to devices, systems, and methods of determining the location of personnel working under hazardous conditions outdoors and/or within one or more structures.
Personal navigation and tracking systems are being developed today for use in any number of applications. In one example, personal navigation and tracking systems may be useful in military applications for tracking and directing the movements of military personnel during military practice maneuvers and/or military battlefield environments. In another example, personal navigation and tracking systems may be useful in field service applications for tracking field service personnel and/or a fleet of vehicles that have been dispatched into the field. In yet another example, personal navigation and tracking systems may be useful in first responder applications for tracking and directing the positions of, for example, law enforcement personnel at the scene of a crime or accident, firefighters at the scene of an accident or fire, and/or emergency medical services (EMS) personnel at the scene of an accident.
Firefighters, first responders, and military personnel work in the world's most dangerous occupations in some of the world's most hazardous environments. Firefighters can easily become disoriented or separated since most firefighting is done in zero visibility as a result of smoke. First responders constantly place themselves in danger, which sometimes results in becoming trapped or disabled. Military personnel face dangerous conditions on a daily basis, and knowing where each soldier is located, whether performing routine tasks or under hostile fire, would be extremely valuable to the commanding officer. In all cases, there are examples where fatalities might have been prevented or injuries lessened in severity with a location system that provides location information about a person in need of assistance to other personnel to find that person relatively quickly.
In cases in which personnel are outdoors, global positioning system (GPS) devices and solutions can, for example, be used to roughly locate such personnel. However, multipath propagation problems lead to poor signals and inaccurate results with GPS devices when used within a structure. Moreover, without significant processing, GPS devices are typically accurate to approximately ±3 meters. Although such inaccuracy can be acceptable for locating personnel and objects outdoors, an inaccuracy of 3 meters within a structure can, for example, result in sending a rescue team to a wrong floor within the structure and thus squandering precious time in a rescue mission. Like GPS devices, some localization devices which use, for example, radio frequency energy, ultrasound energy and/or infrared energy, can suffer from multipath propagation problems, leading to substantial inaccuracy when used within structures.
With respect to first responder applications, firefighters have lost their lives because of the lack of effective indoor navigation and tracking systems. As a result, there is particular interest in developing effective navigation and tracking systems for indoor use. Traditional systems for navigating indoors, such as within a building, are generally costly or ineffective. For example, the installation and operating costs associated with an installed base of radio frequency markers within a building are substantial barriers not readily overcome. In addition, poor reception of radio frequency navigation signals within a building, such as that used by satellite-based navigation systems, precludes widespread acceptance.
More specifically, indoor environments pose particular challenges with respect to implementing navigation and tracking systems. For example, signal transmission in indoor environments may be characterized by the presence of reflections, attenuation, low signal to noise ratio, and signal multipath effects; all of which may decrease tracking accuracy and may prevent signal acquisition all together. Further, multiple story buildings pose additional obstacles for tracking, as they require three-dimensional positioning.
One type of navigating system is an inertial navigation system (INS), which is a navigation aid that uses a computer and motion sensors to continuously calculate via dead reckoning the position, orientation, and velocity of a moving object without the need for external references. Inertial navigation systems are used in many different moving objects, including vehicles, aircraft, submarines, spacecraft, and guided missiles. However, their components size, cost, and complexity places constraints on the environments in which INS is practical for use.
An INS includes at least a computer and a platform or module containing accelerometers, gyroscopes, or other motion-sensing devices. A typical INS is initially provided with its position and velocity from another source (a human operator, a GPS satellite receiver, etc.), and thereafter computes its own updated position and velocity by integrating information received from the motion sensors. The advantage of an INS is that it requires no external references in order to determine its position, orientation, or velocity once it has been initialized.
The initialization and deployment process represents one key component in using an INS, such as a boot-mounted INS-based personal navigation system, wherein multiple users are being tracked in a given environment. For example, if multiple responders will be entering a building or structure, they must somehow be coordinated relative to each other in order to effectively track their position.
In view of the shortcomings of the aforementioned navigation and tracking systems, a need exists for new approaches to personal navigation and tracking. In particular, a need exists for a practical and cost-effective personal navigation and tracking system that is highly accurate and reliable in any environment and that is suitable for use in any application, such as, but not limited to, military applications and first responder applications. It is further desirable to develop improved devices, systems, and methods of determining the location of mobile personnel that reduce the severity of or eliminate the above-described and other problems with current location devices, systems and methods. It is additionally desirable to develop a navigational system initialization system and arrangement for determining a common frame of reference (or coordinate system) between multiple users.